BIOLOGYOption A

Topic Outline

Diet

Biochemistry of Nutrition

Diet and Health

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Option A.1 - Diet

A.1.1 State the diet is the total food taken in by an individual.

Diet is the total food taken in by an individual.

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A.1.2 Define nutrient.

A nutrient is a chemical that an animal requires but cannot make itself. It is already

in complete form when taken in.

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A.1.3 List the constituents of a diet including carbohydrate, protein, lipid, minerals,

vitamins, water and fiber.

In a diet, carbohydrates, proteins, lipids, minerals, vitamins, water, and fiber are needed.

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A.1.4 Explain the functions of the constituents listed above.

Carbohydrates can be used as fuel for the generation of ATP. Lipids are also used for this, they are rich in energy. Proteins are sometimes used for ATP production as well. They also regulate the amount of sugar in the blood

and transport oxygen.

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Vitamins are needed for many functions of the body, such as for metabolism, blood clotting, and absorption of other things in the body.

Minerals help in bone formation and structure as wel as help enzymes function, help in

metabolism, and water balance.

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Water is needed because the organs need to stay wet and the body is made mostly of water. Fiber is needed by the digestive system in order to digest foods properly.

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A.1.5 Describe a balanced diet as an equilibrium between food intake and energy expenditure

and in terms of meeting bodily needs for growth, replacement and healthy functioning.

When a balanced diet exists, fuel for cellular work of the body is provided, the organic raw materials animals use in biosynthesis are there, and essential nutrients that an animal cannot make for itself is

taken in in prefabricated form.

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When the body is undernourished, meaning there is no balanced diet, muscles fan decrease in size, the person is lethargic, and the brain

may become protein-deficeint

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A.1.6 Evaluate common packaged food items by interpreting the dietary

information printed on them.

Look at nutrient content, lipid content, carbohydrate content, protein, fiber, vitamins and minerals.

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A.1.7 Calculate, compare and evaluate the nutritional content of foods and diets.

This is a type of paper 2 question that there will hopefully eventually be an example of.

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Option A.2 - Biochemistry of Nutrition

A.2.1 List two sources for each of monosaccharides, disaccharies and

polysaccharides in a diet.

Two sources of monosacharrides are milk and fruits. Two sources of disaccharides

are table sugar and milk sugar. Two sources of polysaccharides are cellulose

and starch.

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A.2.2 Outline the uses of absorbed carbohydrates including cell respiration, energy storage

(glycogen or fat), synthesis of glycoproteins, nucleic acids and some amino acids.

A.2.3 List three sources of lipids in the diet.

Three sources if lipids in a diet are oils that you cook things in, butter and/or dairy

products, and meats.

A.2.4 Outline the uses of absorbed lipids including energy storage, insulation, membranes

and cell respiration.

Fats and oils are stored in the body and released by cell respiration.

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They conduct heat slowly and because of the body's adipose tissue, the fat ascts as a thermal

insulator. Phospholipids are the main consituents of membranes. Cell respiration is what

releases energy stored in the fat.

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A.2.5 Discuss the variation in energy requirements (in kJ or MJ) depending on age, gender,

activity and cell respiration.

With increasing of age, adulthood requires more energy as the body grows larger.

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Females use less energy than males - smaller body size and less heat loss because of thicker fat layers. The more vigorous an activity is, the more energy that is

required. Extra energy is needed during growth spurts, pregnancy, breast-feeding, illnesses,

and some other conditions

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A.2.6 List four sources of protein in a diet.

Sources of protein are beef, fish, seeds, nuts, and soybean products.

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A.2.7 Outline the fate of the products of ingested protein including protein

synthesis and deanimation.

Proteins are digested into amino acids which are absorbed and used in protein synthesis.

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If there is an excess of amino acids some are broken down by removing amino groups

from them, called deanimation. The remainder of the molecule can later be released

in cell respiration.

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A.2.8 State that essential amino acids are those which must be ingested and

cannot be synthesized.

Essential amino acids are those that must be ingested and cannot be synthesized

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A.2.9 Explain the general importance of vitamins and minerals in the diet.

Vitamins are needed because without them, serious disorders can occur, such ass nervous

disorders. Minerals are important for bone development and nervous system development.

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A.2.10 State one function of iodine and zinc.

Zinc is a component of certain digestive enzymes and other proteins. Iodine

is a component of thyroxine.

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A.2.11 Outline the functions of the following vitamins. Retinol, cyanocobalamin, ascorbic acid, calciferol, and tocopherol.

Retinol is also known as vitamin A. Retinol is a component of visual pigments, it is needed for maintenance of epithelial tissues, its an

antioxident, and helps prevent damage to lipids of cell membranes.

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Cyanocobalamin is also known as vitamin B12. Cyanocobalamin is a coenzyme in nucleic acidmetabolism and is also needed for maturation

of red blood cells. Ascorbic acid is also known as vitamin C.

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Ascorbic acid is used in collagen synthesis, its an antioxidant, it aids in detoxification, and it

improves iron absorption. Tocopherol is also known as Vitamin E. Tocopherol is

an antioxidant, it helps prevent damage to lipids of cell membranes.

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A.2.12 Discuss the importance of fiber in a diet.

Fiber may help prevent obesity by increasing the bulk in the stomach which reduces

the desure to eat more food.

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Fiber may reduce the risk of diseases of the large intestine including appendicitis cancer andhemorrhoids. Fiber may reduce the rate of absorption of sugar and so help the prevention and treatment of diabetes.

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Option A.3 - Diet and Health

A.3.1 Discuss the significance of diets which are rich in lipids in relation to obesity and coronary heart disease.

Diets that are rich in lipids cause obesity because of the high energy content of

lipids.

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They can also increase the risk of coronary heart disease. This involves the formation of blood clots which can block the coronary arteries. These arteries supply the heart with blood. The accumulation of fat and cholesterol in the artery wall cause blod clots to form.

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A.3.2 Explain the significance of saturated and unsaturated lipids

in relation to healthy diet.

Saturated lipids have no double bonds between their carbon atoms

and are mainly found in animal products.

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These types of fats can cause coronary heart disease. Polyunsaturated lipids have two or more double

bonds between their carbon atoms and are mainly found in plant products. Levels of these two kinds of fat are not significant.

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A.3.3 State that the liver synthesizes cholesterol.

The liver synthesizes cholesterol

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A.3.4 Outline how the body uses cholesterol in cell membranes and in the synthesis

of some hormones.

Cholesterol is found mainly in animal products. It is an essential component of cell membranes

and is used in the synthesis of steriod hormones such as estrogen, progesterone, and testosterone.

The amount of cholesterol in a diet does not affect the blood cholesterol that much.

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A.3.5 Discuss the effects of additional dietary cholesterol.

Other aspects of the diet are more significant than the affect of added cholesterol. This added cholesterol does not affect the blood cholesterol level that much

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A.3.6 Distinguish between vegan and vegetarian diets.

Vegans include no anilmal products in their diet. They don't eat meat, fish, milk, butter, cheese,

or any other dairy products, eggs, or honey. Vegetarion diets usually include eggs, milk,

butter, cheese, and other dairy products, and exclude meat and fish.

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A.3.7 Discuss the ethical issues surrounding the eating of meat,

fish, eggs and diary products.

Some of the ethical issues include taking the life of other animals for food, justifying

the pain caused to the animals in transport and slaughter, justifying the suffering of animals

just to fix crowded conditions, taking animals from their natural habitats, is the pollution

caused by fish farming acceptable.

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A.3.8 Discuss the possibility of a deficiency in calcium, iron , calciferol (vitamin D) and

cyanocobalamin (vitamin B12) in vegetarian and vegan diets.

Deficiencies are unlikely in vegetarian diets. Vegans risk cyanocobalamin

deficiency and could benefit from a supplement of it. Zinc, found in red meat, seafood and

egg yolks, can also be obtained from yeast and cereals.

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Calciferol, found in milk, egg yolks and liver, is not needed as long as vegans receive

sufficient sunlight.

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A.3.9 Define malnutrition.

Malnutrition isa condition where the diet is not balanced.

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A.3.10 Suggest how malnutrition can be caused by any (or a combination) of social,

economic, cultural and environmental conditions.

It may be hard to buy food because of poverty, or crops grown by farmers might have to be sold instead of eaten. Lack of

investment may make farming inefficient.

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Droughts or floods might destroy crops. Mineral deficiciencies in soils may cause deficiencies in humans. Population growth may make the food

supply insufficient. Disruption to society caused by wars or corrupt government may prevent the

production or distribution of food.

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Diet is part of the culture of a population. Cultures that have a diet mostly of maize tend to suffer from pellegra - vitamin B3 dificiency and cultures that

have a diet mostly of polished rice tend to suffer from beri-beri - vitamin B1 deficiency.

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A.3.11 Discuss one example of global malnutrition using published data.

Iodine deficiency disorder involves swelling of the thyroid gland in the neck. This is called a goitre.

UNICEF publishes data on IDD rates of 6-11 year old children. Countries

with the highest rates are:

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Albania 41%, Bangladesh 50%, Central African Rep. 63%, Guinea 55%, Lesotho 43%, Nepal 44%, Paraguay 49%, Rwanda 41%, Syria 73%,

Zambia 51%.

They began to sell quantities of salt and these numbers have been going down.

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A.3.12 Discuss the relationship between nutrition and each of rickets,

anemia and osteoporosis.

Rickets is a disease of childhood where a childs legs become bowed because the bones

do not have enough calcium salts to strengthen them. It's usually caused by

vitamin D deficiency.

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Anemia is a deficiency of red blood cells or hemoglobin. It can be caused by iron deficiency, vitamin B12 deficiency, folic acid or acsorbic acid

deficiency. Osteoporosis is aprogessive loss of mass from bones, making them brittle and easily fractured.

Calcium and calciferol deficiencies have some cause. Also estrogen levels are a factor.

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A.3.13 State that chemical additives can act as preservatives, antioxidants, colorings,

flavorings, stabilizers and acid-regulators.

Chemical additivies can act as preservatives, antioxidants, colorings, flavorings,

stabilizers and acid-regulators.

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A.3.14 Outline three possible harmful effects of named food additives.

Nitrite is added to cured meats and fish as a preservative. It reacts with amino acids in the gut to

produce mitrosamines, which are highly carcinogenic.

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Tartrazine is used in drinks and foods as yellow colouring. It have a variety of harmful effects

including asthma, skin rashes, and hyperactivity. Monosodium glutamate is added to many foods to act as a floavour enhancer. Some people suffer

allergic reactions, including sweating, rapid heartbeat and headache.

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A.3.15 Explain the importance of using hygienic methods to handle and prepare food.

This is important because food poisoning can be fatal. Foods need to be cooked thoroughly

to kill any possible bacteria.

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Frozen food must be fully defrosted before cooking. Cooked and uncooked food must be stored separately to avoid bacteria passing from uncooked

to cooked food. Food must not be eaten after its 'use by' date. Flies and other animals must not

be allowed to contaminate food.

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